Corticosteroid injections into the epidural space or sacroiliac joint are increasingly used for the treatment of chronic neck, low back, and leg pain. These injections may have several side effects, including suppression of the body's adrenal glands to produce steroids (adrenal suppression) and negative effects on metabolism (weight gain, increased blood pressure, and high blood sugar levels).

The purpose of this study is to determine the time course and predictors of adrenal suppression and the metabolic effects of corticosteroid injections for chronic pain.

The investigators hypothesize normalization of adrenal function to occur within three weeks of injection in most individuals. An increased frequency of injections is predicted to lead to prolonged adrenal suppression. Corticosteroid injections are also hypothesized to lead to increases in body weight, blood pressure, and blood sugar levels, particularly in diabetic individuals.

Time to Normalization of Hypothalamic-Pituitary-Adrenal Axis (HPAA) Function Following Epidural or Sacroiliac Joint Corticosteroid Injection [ Time Frame: From date of enrollment (Baseline) until the date of HPAA normalization assessed every 3 weeks up to 6 months ] [ Designated as safety issue: No ]

The high-dose rapid adrenocorticotropic hormone (ACTH) stimulation test will be performed to determine if HPAA suppression is present. Serum cortisol will be measured by electrochemiluminescence immunoassay immediately prior to and at 30 and 60 min following injection of 250 mcg cosyntropin IV. A serum cortisol level <550 nmol/L (<20 mcg/dL) at either time point following cosyntropin administration will designate HPAA suppression.

Consecutive patients receiving initial or repeated sacroiliac joint or single or multi-level epidural corticosteroid injections as part of their management plan for SI joint, neck, back, or radicular pain. Injections will be performed using 0.5 mL bupivacaine 0.25% and 15 mg dexamethasone sodium phosphate.

Detailed Description:

Interventional pain procedures using corticosteroid injections (CIs), such as epidural steroid injections (ESIs) and sacroiliac joint injections (SIJIs), may have adverse metabolic and endocrine effects, including suppression of the hypothalamic-pituitary-adrenal axis (HPAA), hypertension, weight gain, and hyperglycemia. Based on sparse data on these adverse effects following repeated, long-term CIs, current guidelines suggest a maximum frequency of four to six injections annually, even though patients may benefit from more frequent treatments.

This prospective cohort study will follow first-time or repeat ESI or SIJI patients receiving injections with 0.5 mL bupivacaine 0.25% and 15 mg dexamethasone sodium phosphate at a maximum frequency of once every six weeks in order to:

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Please refer to this study by its ClinicalTrials.gov identifier: NCT01717430